From document FR-0,707,406, an updating device is known comprising means for calculating an updating bias and for adding such an updating bias to any new position of the aircraft. Such an updating bias illustrating a position error of the aircraft could be determined:                either by the aircraft flying over a spot on the Earth, with the bias corresponding to the deviation between the position of the spot being flown over (stored in a database) and the current position of the aircraft while flying over;        or by means of a radar, the bias corresponding to the deviation on a radar display between the position of a particular spot seen by the radar and the position of such a spot in a data base.        
It is known that determining, updating and taking into account the position of an aircraft occur at the level of a set of systems in the aircraft, generally comprising a GADIRS (<<GPS Air data Inertial Reference System>>) type inertial and anemometric reference system and, connected to the latter, more specifically a FCGS (<<Flight Control Guidance System>>) type flight calculation system and a FMS (“Flight Management System”) type flight management system. Furthermore, in such a usual architecture, the flight management system generally comprises:                a means for supplying a first consolidated GPIRS position of the aircraft, being determined from inertial data and data supplied by a satellite positioning system, including the GPS (“Global Positioning System”) type;        an inertial and radio-navigation calculation means for supplying a second IR/Navaids position of the aircraft, being determined from inertial data and data supplied by radio-navigation means (VOR, DME, TACAN); and        selection means for selecting one of said first and second positions, that will be taken into account as a position updated by said flight management system.        
Generally, in such a usual architecture:                the GPIRS position is updated at the level of the GADIRS system and the IR/Navaids position is updated at the level of the FMS system, which makes necessary implementing a complex interface (comprising a dating of data) between GADIRS and FMS systems, for exchanging updated positions;        updating the position occurs via means for correcting the bias at the level of GADIRS and FMS systems;        the FCGS system comprises means for subtracting the biases from the updated GPIRS positions received from the GADIRS system, so as to avoid a position used by said FCGS system (that should be quite accurate) from being impacted by a bias taken into account by said GADIRS system; and        only manual updates are provided (through flying over or using a radar) being triggered and managed by a crew member.        
Such a usual architecture that seems complex and expensive is not fully satisfactory.